Deep-learning-based estimation of left ventricle myocardial strain from echocardiograms with occlusion artifacts

We present a deep-learning-based methodology for estimating deformation in 2D echocardiograms. The goal is to automatically estimate the longitudinal strain of the left ventricle (LV) walls in images affected by speckle noise and acoustic occlusions.

The proposed methodology integrates algorithms for converting sparse to dense flow, a Res-UNet architecture for automatic myocardium segmentation, flow estimation using a global motion aggregation network, and the computation of longitudinal strain curves and the global longitudinal strain (GLS) index. The approach was evaluated using two echocardiographic datasets in apical four-chamber view, both modified with noise and acoustic shadows. The CAMUS dataset ( $N=250$ ) was used for LV wall segmentation, whereas a synthetic image database ( $N=2037$ ) was employed for flow estimation.

Among the main performance metrics achieved are 98% [96 to 99] of correlation in the conversion from sparse to dense flow, a Dice index of $88.2\%\pm 3.8\%$ for myocardial segmentation, an endpoint error of 0.133 [0.13 to 0.14] pixels in flow estimation, and an error of 1.34% [0.94 to 2.09] in the estimation of the GLS index.

The results demonstrate improvements over previously reported performances while maintaining stability in echocardiograms with acoustic shadows. This methodology could be useful in clinical practice for the analysis of echocardiograms with noise artifacts and acoustic occlusions. Our code and trained models are publicly available at https://github.com/ArBioIIMAS/echo-gma.